Thermometer.



' No.861,246. PATENTED JULY 30, 1907.

E. L.v BAKER.

THERMOMBTER.

APPLICATION FILED Ame, 1901.

[NI ENTOR.

PATENT @FFTQ.

EUGENE L. BAKER, OF TAUNTON, MASSACHUSETTS.

THE RMOMETER.

Specification of Letters Patent.

Patented July 30, 1907'.

Application filed April 6, 1907. Serial No. 366,775-

To all whom it may concern:

Be it known that I, EUGENE L. BAKER, a citizen of the United States, residing at Taunton, in the county of Bristol and State of Massachusetts, have invented a new and useful Thermometer, of which the following is a specification.

My present invention relates to improvements in thermometers and more especially to that class employed for determining the temperature of ovens, and it has for its object to provide an improved device of this character having elements of different coefficients of expansion arranged in a manner that facilitates assembling of the devices and prevents displacement of its parts, which is of particular importance when the device is attached to an oven door, and it also provides a frame that is so constructed as to afford ample resilionce to permit a delicate operation of the device, and, furthermore, it provides an improved mounting for the needle or indicator that enables the latter to be readily applied and is capable of indicating the delicate movements of the parts of the frame without the necessity of employing gearing and similar multiplying mechanism.

To these and other ends, the invention comprises the various novel features of construction and combination and arrangement of parts, which will be hereinafter more fully described and pointed out particularly in the claims appended hereto.

In the accompanying drawings:--Figure 1 is a front elevation of a thermometer constructed in accordance with the present invention, portions being broken away to show the construction of its parts. Fig. 2 represents a section on the line 22 of Fig. 1. Fig. 3 is a detail view showing the mounting for the needle or indicator as viewed from the rear.

Corresponding parts in the several figures are indicated throughout by similar characters of reference.

The device shown in the present embodiment of my invention embodies a resilient frame composed of cast iron or other suitable material having a relatively low coefficient of expansion, the frame shown in the present instance embodying a relatively stationary intermediate portion 1.11aving an inwardly extending lug 2 thereon that may be employed for attaching the device to an oven door or other suitable support, and it may also serve as a mounting for an appropriate scale 3 that is provided with thermometer calibrations. Extending divergently relatively to the intermediate portion are a pair of side arms 4 and 5, the lower ends of these arms being turned inwardly to form the indicator or needle supporting portions 6 and 7, the arms, in the present instance, being of equal length and the inturned portion 6 being provided with an offset 8 in order that the needle or indicator supportiong portions may overlap one another, the inner ends of these portions lying in close proximity one above the other and having sufficient clearance to permit a relatively longitudinal movement thereof as the angular relation of the arms of the frame varies according to the heat variations. In order to permit relative angular movements of these arms, they are connected at their upper ends to the intermediate portion of the frame by means of loops 9 and 10 that are formed by bends in the metal in a plane parallel to the arms of the frame.

The expansion members 11 and 12 for actuating the arms of the frame according to the temperature variations embody in the present instance substantially straight bars having their ends fitted into seats or recesses 13 formed in the intermediate portion and with correspondingly formed recesses 14 formed in the frame substantially at the point of juncture of the side arms and the inturned needle supporting portions, these members being composed of brass or other suitable material having a coefficient of expansion higher than that of the material composing the frame, so that a rise in temperature will cause a greater expansion of the expansion members that will increase the angle between the arms of the frame.

The needle or indicator 15 has a pointer 16 thereon adapted to cooperate with the scale, the lower end of the needle being provided with a journal portion 17 turned at right angles to the main portion thereof and extending through an aperture arranged transversely of the inner end of the needle actuating and supporting portion 7, the end of the journal portion being bent to extend in a direction longitudinally of the needle, as at 18, and finally doubled parallel to the journal 17 to form an operating end 19, the latter cooperating with a transverse recess or slot 20 formed in the inner end of the needle supporting'and actuating portion 6, the operating and the journal portions of the needle being so located relatively to one another that the relative movements of the portions 6 and 7 in a direction longitudinally thereof will impart an amplified movement to the pointer on the free end of the needle.

A thermometer constructed in accordance with the present invention may be manufactured and sold at a low price, as the frame may be cast of a single piece, it being so constructed that ample resilience is afforded to permit the indicator actuating portions thereof to sion members are mounted in the seats or recesses in the frame and are held therein by the spring action of the latter, assembling of the devices will be very easily accomplished and the expansion members cannot become displaced by reason of vibrations due to the opening and closing of the oven door. The mounting of the indicator permits the latter to be readily applied and operate within the required limits, and as the expanit affords ample sensitiveness without the necessity of employing gearing or other complicated mechanism for amplifying the movement;

What is claimed is:

1. In a thermometer of the character described, the coinbination with a frame composed of a material having a relatively low coefiicient of expansion and embodying an in termediate portion, a pair of arms having cooperatively arranged needle actuating portions, and loops resiliently conmeeting the said arms to the intermediate portion, of an expansion member for each arm, the loops being formed in each arm at points intermediate the parts engaged by the ends of the respective expansion member, and a needle arranged to be operated by the needle actuating portions of the said arms.

2. In a thermometer of the character described, the combination with a frame embodying an intermediate portion, a pair of arms resiliently connected thereto and provided with needle actuating portions on their free ends, the intermediate portion of the frame and portions of the arms in proximity to their free ends being provided with seats or recesses, of expansion members having their ends pivoted in the seats of the intermediate portion and the arms of the frame, a loop in each arm of the frame at a point between the parts engaged by the ends of the respective expansion member, and an indicator operatively connected with the needle actuating portions of the frame.

3. In a thermometer of the character described, the 00111 bination with a frame embodying a pair of divergently arranged arms connected at their proximate ends by a pair of resilient loops and having their opposite ends extending inwardly and overlapping one another to form indicator actuating portions, the frame being provided at points intermediate the loops and at points adjacent to the junctures of the arms and on the indicator actuating portions with seats or recesses, of expansion bars extending substantially parallel to the arms' respectively of the frame and having their ends fitted into the seats thereof, the loops being formed in the arms of the frame at points between the seats thereof engaging the ends of the respective expansion members.

4. A thermometer of the character described embodying .a resilient frame having a pair of relatively movable arms and provided with inturned overlapping ends, one of the ends being provided with a transversely extending aperture and the other end being provided with a transversely ar ranged slot, and an indicator having a journalportio'n fitting in' said aperture and having a portion bent laterally of the journal portion and cooperating with the slot in the upper end, relative longitudinal movement of the ends serving to rotate the indicator about the journal portion thereof as an axis.

In testimony that I claim the foregoing as my own, I have hereto aflixed my signature in the presence of two witnesses.

EUGENE L. BAKER.

Witnesses:

FRANK C. DEAN, CAnLn'roN F. SANFORD. 

